16
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Fast and easy super-sample covariance of large scale structure observables

      Preprint
      ,

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          We present a numerically cheap approximation to super-sample covariance (SSC) of large scale structure cosmological probes, first in the case of angular power spectra. It necessitates no new elements besides those used for the prediction of the considered probes, thus relieving analysis pipelines from having to develop a full SSC modeling, and reducing the computational load. The approximation is asymptotically exact for fine redshift bins \(\Delta z \rightarrow 0\). We furthermore show how it can be implemented at the level of a Gaussian likelihood or a Fisher matrix forecast, as a fast correction to the Gaussian case without needing to build large covariance matrices. Numerical application to a Euclid-like survey show that, compared to a full SSC computation, the approximation recovers nicely the signal-to-noise ratio as well as Fisher forecasts on cosmological parameters of the \(w\)CDM cosmological model. Moreover it allows for a fast prediction of which parameters are going to be the most affected by SSC and at which level. In the case of photometric galaxy clustering with Euclid-like specifications, we find that \(\sigma_8\), \(n_s\) and the dark energy equation of state \(w\) are particularly heavily affected. We finally show how to generalize the approximation for probes other than angular spectra (correlation functions, number counts and bispectra), and at the likelihood level, allowing for the latter to be non-Gaussian if needs be.

          Related collections

          Author and article information

          Journal
          14 September 2018
          Article
          1809.05437
          fddd8147-a02e-4512-a2ca-a60505cdec38

          http://arxiv.org/licenses/nonexclusive-distrib/1.0/

          History
          Custom metadata
          main text: 9 pages, 3 figures ; appendices: 4 pages, 1 figure
          astro-ph.CO

          Cosmology & Extragalactic astrophysics
          Cosmology & Extragalactic astrophysics

          Comments

          Comment on this article